When sowing seeds outdoors, work up the soil in a protected location in early to mid-November. Scatter the seeds over the prepared seed bed and then cover the seeds with approximately 1/4 inch of soil. The cold, moist conditions over winter improve seed germination. Seedlings should emerge in spring. Carefully transplant the seedlings to their permanent locations when the seedlings are 3 to 4 inches tall.
Harvest the seed pods of butterfly weed when the pods begin to split. Seeds can be sown directly outdoors in late fall or started indoors.
To start seeds indoors, fill a flat with a commercial germination medium (such as Jiffy Mix). Moisten the medium. Scatter the seeds over the surface of the germination medium and lightly press the seeds into the material. Cover the seeds with an additional 1/4 inch of the germination mix. Carefully moisten the additional material. Slide the flat in a plastic bag and place the bagged flat in the refrigerator. Leave the flat in the refrigerator for 4 to 6 weeks. After 4 to 6 weeks, remove the flat from the refrigerator and place it in an area with a temperature of 70 to 75 degrees Fahrenheit. Seeds should begin to germinate in 3 to 4 weeks. (If no seedlings appear after 4 weeks, place the flat back in the refrigerator for another 4 to 6 weeks and repeat the process.) Take the flat out of the plastic bag as soon as seedlings appear and place the flat under fluorescent lights in a 60 to 65 degree Fahrenheit location. Transplant the seedlings into individual pots when the seedlings are 1 to 2 inches tall. Continue to grow the seedlings indoors under fluorescent lights for several more weeks. Prior to planting outdoors, place the seedlings outdoors in a shady, protected location and then gradually expose the seedlings to longer periods of direct sun. Plant the seedlings in their permanent locations after they have hardened outdoors for 10 to 14 days.
This photograph from Wikipedia speaks volumes to the importance of the milkweed. Asclepias tuberosa is a favored nesting site for the Monarch butterfly. At summers end, the wild plants we have growing at the shop will be covered with their larvae. The Monarch larvae feed on these leaves. The butterfly weed is a favored host in my area. They will spin cocoons; the mature butterflies will emerge some four weeks, give or take. Only once have I witnessed a mature butterfly emerging from its chrysalis-it happens that fast.
Our local fields and meadows are full of the remains of the milkweed pods come November. They have an elegantly spare and ruggedly persistent shape.
Any landscape designers best ally is what comes from the natural world. All it takes is a lot of observation, and then some serious thought. As my friend and colleague Susan Cohan says, art does not necessarily have to work. No artwork needs a white silky airplane to be. A work of art lives independent of time,conditions, and circumstance. Good landscape design is a craft, in that every moment needs to assess the conditions, fire up,and fly.